code: def pytest_addhooks(pluginmanager):
      if not _installed:
          return
      # https://github.com/pytest-dev/pytest-xdist/blob/974bd566c599dc6a9ea291838c6f226197208b46/xdist/plugin.py#L67
      # avoid warnings with pytest-2.8
      from dash.testing import (
          newhooks,
      )  # pylint: disable=import-outside-toplevel
  
      method = getattr(pluginmanager, "add_hookspecs", None)
      if method is None:
          method = pluginmanager.addhooks  # pragma: no cover
      method(newhooks)
  
file_path: dash/dash/testing/plugin.py
imports: import pytest
  from .consts import SELENIUM_GRID_DEFAULT
label_desc: Use image node_id 2 for calling a global function with example usage: pytest_addhooks(pluginmanager) without return types